cuyahoga county department of public...

CUYAHOGA COUNTY

DEPARTMENT OF PUBLIC WORKS

CUYAHOGA COUNTY ENGINEER DRAINAGE MANUAL

Supplement to

O.D.O.T. LOCATION and DESIGN MANUAL, Volume 2,

Drainage Design, Section 1000 and 1100

July 29, 2011

Revisions to the May 28, 2010 edition are noted by a vertical line in the right page margin.

INTRODUCTION

Volume Two, Sections 1000 and 1100 of the O.D.O.T. Location and Design Manual,

except as modified herein, together with this supplement, shall be applicable to all

Cuyahoga County funded County Road or Bridge improvement projects. It is the objective

of this manual to supplement O.D.O.T. drainage policy and also to indicate the differences

between Cuyahoga County policy and O.D.O.T. policy. In order to facilitate cross-

referencing, the topic headings and section numbers used in this manual correspond to

those in the Location and Design Manual.

Where references are made to the State, the Administrator/Office of Hydraulic

Engineering (OHE), or any other term designating any representative or employee of the

State, or the Department of Transportation, as found in Sections 1000 and 1100 of the

O.D.O.T. Location and Design Manual, such references shall alternately mean Cuyahoga

County, The Cuyahoga County Department of Public Works, the Cuyahoga County

Engineer, the Cuyahoga County Chief Highway Design Engineer and the Cuyahoga

County Chief Bridge Design Engineer.

When a municipality has a written drainage policy, which the municipality desires to

apply to a county funded County Road or Bridge improvement project, the Chief Highway

Design Engineer or Chief Bridge Design Engineer shall review the municipality's policy and

determine if such policy is appropriate for use on the project.

CCE Drainage Manual 07-29-11 Page 2

TABLE OF CONTENTS

SECTION REVISION

NUMBER SUBJECT DATE PAGE

1001 Cuyahoga County Hydraulic Design

Policy 07/29/2011 4

1002 Cuyahoga County Pipe Policy 09/26/2007 5

1004 Flood Clearance 05/22/1995 6

1006 Culvert Allowable Headwater 02/01/2000 6

1009 Subsurface Pavement Drainage 05/28/2010 6

1101 Estimating Design Discharge 09/26/2007 7

1102 Open Water Carriers 07/29/2011 8

1103 Pavement Drainage 07/29/2011 9

1104 Storm Sewers 07/29/2011 11

1105 Roadway Culverts 07/29/2011 13

1109 Longitudinal Sewer Location 09/26/2007 13

1111 Sanitary Sewers 07/29/2011 14


TABLE OF CONTENTS (Cont.)

REVISION

SUBJECT DATE PAGE

Supplements to Appendix A and Drainage Design Aids 15

3C Catch Basin Bypass Charts 05/22/1995 16-23

Cross Slope = 3/16" per foot 16







Cross Slope = 1" per foot 23

No. 3C Catch Basin Spacing Form Instructions 02/01/2000 24

No. 3C Catch Basin Spacing Form (English Units) 06/01/2000 25

No. 3C Catch Basin Spacing Form (Metric Units) 06/01/2000 26

Cuyahoga County Storm Sewer Computation Form Instructions 02/01/2000 27-28

Cuyahoga County Storm Sewer Computation Form (English Units) 06/01/2000 29

Cuyahoga County Storm Sewer Computation Form (Metric Units) 06/01/2000 30

Cuyahoga County Culvert Calculation Form (English Units) 06/01/2000 31

Cuyahoga County Culvert Calculation Form (Metric Units) 06/01/2000 32


(1001) CUYAHOGA COUNTY HYDRAULIC

DESIGN POLICY

1001.1 Responsibilities

Depending on which office manages the project, the Cuyahoga County Chief Highway

Design Engineer or the Cuyahoga County Bridge Design Engineer is responsible for the

hydraulic and structural design approval of all prefabricated structures having a span of less

than twenty feet (6.1 meters) and all standard headwalls or endwalls used in conjunction with

these structures.

The Cuyahoga County Chief Bridge Design Engineer is responsible for the hydraulic and

structural design approval of all prefabricated structures having a span of twenty feet (6.1

meters) or greater and all headwalls or endwalls used in conjunction with these structures.

He also is responsible for the structural design approval of all non-standard headwalls or

endwalls used in conjunction with prefabricated structures having a span of less than twenty

feet (6.1 meters).

The Cuyahoga County Chief Bridge Design Engineer is responsible for the structural design

approval of all cast-in-place structures regardless of structure size and for the hydraulic

design approval of cast-in-place structures having a span of twenty feet (6.1 meters) or

greater.

Depending on which office manages the project, the Cuyahoga County Chief Highway

Design Engineer or the Cuyahoga County Bridge Design Engineer is responsible for the

hydraulic design approval for cast-in-place structures having a span of less than twenty feet

(6.1 meters).

1001.2 Natural Streams

Channel designs and channel relocations of all natural streams passing through a proposed

highway facility are the responsibility of the Chief Engineer (Bridge or Highway Design)

who is responsible for the hydraulic review and approval for the highway structure.


(1002) CUYAHOGA COUNTY PIPE POLICY

1002.3 Conduit Types

1002.3.1 Type A Conduits

Non-reinforced concrete pipe and clay pipe shall not be specified as Type A conduit. Subject

to the approval of the maintaining agency, all other pipe materials listed under 603.02 (Type

A Conduits) are acceptable. Specify Class III minimum for 706.02 and Class HE-III

minimum for 706.04. Any special designs using alternate materials must be pre-approved by

the County as well as the maintaining agency.

1002.3.2 Type B Conduits

Subject to the approval of the maintaining agency, all pipe materials listed under 603.02

(Type B Conduits) are acceptable. Specify Class III minimum for 706.02 and Class HE-III

minimum for 706.04. Specify Class 3 for 706.01 – Maximum allowable size 21‖ (525 mm).

Specify Extra Strength (ES) for 706.08 – Maximum allowable size 15‖ (375 mm). Provide

706.11 joints for all concrete pipe (706.01, 706.02, 706.04 and 706.05). Provide 706.12

joints for all clay pipe (706.08 ES).

1002.3.3 Type C Conduits


(Type C Conduits) are acceptable. Specify Class 3 for 706.01 – Maximum allowable size 21‖

(525 mm). Specify Extra Strength (ES) for 706.08 – Maximum allowable size 15‖ (375 mm).

Provide 706.11 joints for all concrete pipe (706.01, 706.02, 706.04 and 706.05). Provide

706.12 joints for all clay pipe (706.08 ES).

1002.3.4 Type D Conduits


(Type D Conduits) are acceptable.

1002.3.5 Type E Conduits

Where used, all pipe materials listed under 603.02 (Type E Conduits) are acceptable subject

to approval of the maintaining agency.

1002.3.6 Type F Conduits


(Type F Conduits) are acceptable.


B. Type F non-perforated underdrain outlet pipe material shall be the same as or compatible

with the actually installed perforated underdrain pipe material. Subject to approval of the

maintaining agency, all pipe materials listed under 603.02-Type F Conduits (underdrain

outlets) are acceptable.

(1004) FLOOD CLEARANCE

1004.2 Design Year Frequency

County Roads (2000 ADT and Over) 25-Year

County Roads (Under 2000 ADT) 10-Year

(1006) CULVERT ALLOWABLE HEADWATER

1006.1 Design Storm

As stated in Section 1004.2 of this supplement.

1006.2 Controls

1006.2.1 Design Storm Controls

A. Two (2) feet (0.6 meter) below the tree lawn grade break (berm) elevation typically

located at the right-of-way for a curbed pavement. One (1) foot (0.3 meter) below the

outer edge of graded shoulder (berm) elevation for an uncurbed pavement.

(1009) SUBSURFACE PAVEMENT DRAINAGE

1009.2 Types of Subsurface Drainage

1009.2.1 Pipe Underdrains

For County Roads, typically provide a single row of pipe underdrains on each side of

the pavement regardless of the pavement width.

The size of all underdrain pipe shall be six (6) inch (150mm) diameter unless project

conditions make it necessary to specify four (4) inch (100mm) diameter. For new

construction, four (4) inch (100mm) size underdrain may only be used upon approval of the

Chief Highway Design Engineer and the maintaining agency. All underdrain shall be of the

size specified in the plan/proposal even when the kind of pipe material is not specifically

itemized.


Subject to the approval of the maintaining agency, the following six (6) inch (150mm)

perforated pipe material may be used:

706.06, 706.08, 707.31, 707.33, 707.41, 707.42 (Perforated per 707.31) and

707.45 (Perforated per 707.31).

Subject to the approval of the maintaining agency, the following four (4) inch (100mm)

perforated pipe material may be used when permitted as specified above:

706.06, 706.08, 707.33, 707.41, 707.42 (Perforated per 707.31) and

707.45 (Perforated per 707.31).

Nonwoven or Monofiliment woven filter fabric wrap per 605.03 shall be specified except

when spot (contingency) replacement is called for. Where available outlets permit, a

desirable underdrain depth of 30 inches (750mm) below subgrade should be specified.

Minimum depths of 18 inches (450mm) below subgrade are acceptable. An absolute

minimum depth of twelve (12) inches (300mm) below subgrade may be permitted for rock

cut installations or where warranted for special design conditions.

Designer Note: Reference is made to the Cuyahoga County Engineer's General Plan Note

No. CUY- D13, ―Item 605 — Shallow (Base) Pipe Underdrains With Fabric Wrap, As Per

Plan‖.

(1101) ESTIMATING DESIGN DISCHARGE

1101.2 Procedures

1101.2.1 Statistical Methods

In addition, the SCS Method (TR-20) may be used, if approved by the County's Chief

Bridge/Highway Design Engineer.

1101.2.4 Rainfall Intensity

Note: Figure 1101-2, Area A is used for Cuyahoga County.


(1102) OPEN WATER CARRIERS

1102.3 Ditch Design Criteria for County Roads over 2000 ADT

1102.3.1 Design Frequency

For roadside ditches, whose primary function is pavement drainage, a 2-year frequency storm

shall be used to determine the depth of flow, shear stress and width of ditch lining (if

required). The design frequency criteria for all other ditches shall be as stated.

The depth of flow for any roadside ditch shall be limited to the elevation of the outside edge

of the pavement shoulder. All other ditches shall not be overtopped for the design discharge.

1102.3.1.1 Estimating Design Discharge

Runoff will be estimated by the Rational Method for all roadside ditches.

The drainage area contributing to roadside ditches, whose primary function is pavement

drainage, shall be determined per Section 1103.3 of this supplement.

The drainage area contributing to all other ditches shall be determined based upon suitable

topographic mapping and site observation as required.

Drive pipe conduit types shall be in accordance with Section 1002.3.4 of this supplement.

The headwater shall not exceed the limits in Section 1102.3.1 of this supplement.

1102.3.2 Ditch Protection

Ditch protection shall be in accordance with 1102.3.2 except that a 2-year frequency

event shall be used for roadside ditches as defined in 1102.3.1 above.

1102.4 Ditch Design Criteria for County Roads less than 2000 ADT

1102.4.1 Design Frequency

As stated in Section 1102.3.1 of this supplement.

1102.4.1.1 Estimating Design Discharge

As stated in Section 1102.3.1.1 of this supplement.


1102.4.2 Shear Stress Protection

In accordance with 1102.3.1 above, a 2-year frequency event shall be used for roadside

ditches. A 5-year frequency event shall be used for all other ditches.

(1103) PAVEMENT DRAINAGE 1103.1 General

The following are acceptable catch basins and inlets for curbed Cuyahoga County roads:

(a) Cuyahoga County No. CB-3C.

(b) Cuyahoga County No. CB-3C2 (twin 3C).

(c) Subject to Municipal Engineer approval, O.D.O.T. Pavement Inlets; No. 2A-6 (1.8m),

No. 2A-8 (2.4m), and No. 2A-10 (3.0m).

(d) O.D.O.T. CB, No. 6 (for use with mountable curbs and/or at drives should catch basin

locations at drives be necessary).

(e) Others may be considered upon request or approval of the maintaining agency.

1103.2 Design Frequency

A 2-year design frequency shall be used for all County Roads.

Pavement inlets or catch basins shall be spaced to limit the spread of flow such that a

minimum of 4 feet (1.2 meters) of "dry" pavement remains in the curb lane.

The spread check for 25-year or 50-year storms for underpasses or other depressed roadways

is NOT required.

1103.3 Estimating Design Discharge

Runoff will be estimated by the Rational Method.

The drainage area contributing to the pavement shall be generally considered as 150 feet (45

meters) taken on each side of the roadway centerline, except as follows:

(a) In fill areas where it is evident that there will be no future development, the

contributing area shall be the area of the roadway cross section that drains toward the

pavement.


(b) In highly developed or urbanized areas the actual area draining to the pavement may be

used in lieu of the 150 foot (45 meter) strip, provided the actual area can be clearly

determined from topographic maps and site inspection.

(c) Where the overland slope beyond the right-of-way is away from the roadway, but

where it is likely that future development will cause portions of this area to slope

towards the pavement, the contributing area shall be based on the designer's judgment.

Generally the 150 foot (45 meter) strip shall not be exceeded nor shall a strip less than

the right-of-way width be used.

For contributing areas of 150 feet (45 meter) or less each side of the pavement centerline, the

design storm shall be calculated using a rainfall duration of 15 minutes with an intensity of

2.95 inches/hour (75mm/hour) for the 2-year storm. In existing commercial areas with

mostly paved frontage, the duration time may be 10 minutes.

In the rare event the 150 foot (45 meter) strip is exceeded, the actual time of concentration

shall be used to determine the rainfall intensity assuming it is more than the 15 minute/10

minute durations prescribed above.

1103.6 Bypass Charts for Continuous Pavement Grades

Companion bypass charts for Cuyahoga County 3-C catch basins on various pavement cross

slopes are included in the "Supplements to Appendix A and the Drainage Design Aids". The

Designer should note that the bypass charts as noted above take into account the local two (2)

inch (50mm) pavement depression as detailed on Cuyahoga County Construction Drawing

No. CB-3C.

For metric units, use the English unit bypass charts and convert the resultant answers into

metric units by using the following conversions:

Given: To Get:

English Units Multiply By Metric Units

Feet 0.3048 Meters (m)

Inches Per Foot (in./ft.) 1/12 (decimal slope rate): (m/m)

Feet Per Foot (ft./ft.) 1.0 (decimal slope rate): (m/m)

Cubic Feet Per Second (cfs) 0.028317 Cubic Meters Per Second (m3/s)


1103.7 Grate Catch Basins in Pavement Sags

Cuyahoga County No. CB-3C2 (twin 3C) catch basins shall be provided at the low points of

sag vertical curves. The 2-year design frequency spread of flow at the low point shall be

limited per Section 1103.2 of this supplement. The next upstream Cuyahoga County No.

CB-3C catch basins on each side of the low point shall be located to limit the flow reaching

the sag catch basins such that the spread requirements are not exceeded.

Conservatively assuming the capacity of the Cuyahoga County No. CB-3C2 (twin 3C) catch

basin to be equivalent to the State's standard No. CB-3 catch basin, the standard CB-3

capacity curves in Figures 1103-3 and 1103-4 of the Location and Design Manual may be

used to determine the depth of ponding at the lowpoint.

Evaluating the spread for a 25-year or 50-year event in a depressed sag is NOT necessary.

It should be noted that although the depth of ponding based on grate capacity can be used to

determine the 25-year or 50-year event spread, the hydraulic grade line is more of a

controlling factor at low points of sag vertical curves. The hydraulic grade line requirement

as explained in section 1104.4.2. of this supplement should be checked for a 50 yr. storm at

the low points.

1103.7.1 Data Presentation

Appropriate computer software may be used provided that all the information ordinarily

furnished in the "No. 3C Catch Basin Spacing Form" is clearly presented for review by the

Cuyahoga County Highway Design Office personnel.

(1104) STORM SEWERS

1104.1 General

As stated and as supplemented herein.

The drainage area contributing to the storm sewer system shall be determined from

topographic mapping supplemented by:

(a) Field Observation.

(b) Data from the Municipal Engineer such as municipal sewer maps which may

indicate contributary sewers from side streets, subdivisions or commercial

developments.

In no case shall the drainage area be less than the highway right-of-way.


When the local governmental agency, through whose jurisdiction the highway improvement

passes, desires that runoff from areas in addition to those naturally contributing to the

roadway storm sewer be included in the roadway storm sewer system, the Agreement for the

improvement between Cuyahoga County and the local agency must contain provisions for

the increase in contributary area.

1104.2 Design Considerations

1104.2.1 Storm Sewer Depth

(J) Where outfall conditions permit, depths shall be such that structure footer drains can

outlet to the storm sewer by gravity flow.

(K) When applicable, storm sewers shall be at least as deep as those they replace to ensure

an outlet for existing lateral connections.

Where proposed highway storm sewers or ditches will interfere with existing private drains

carrying treated sanitary flow, the designer must obtain a list of all property owners

authorized to discharge treated sanitary effluent into the storm sewer/ditch system.

This information including residential septic system site plans may be obtained from the

County Board of Health and/or the City/Village Engineer.

1104.4 Storm Sewer Design Criteria

1104.4.2 Hydraulic Grade Line

As stated in the O.D.O.T. Location and Design Manual except that the resultant ponding

based on the 50-year check shall be limited to the top of curb.

The friction slope (Sf) for conduits flowing under pressure may be determined by the

following equation:

(English Units) (Metric Units)

Sf = 4.66n2xQ

2/D

16/3 Sf = 10.29n

2Q

2/D

16/3

Q (cfs) = Q25 Q (m3/s) = Q25

D = conduit diameter (feet) D = conduit diameter (meters)


1104.4.4 Time of Concentration

tc = 15 min. to first ditch inlet/pavement catch basin or 10 min. for mostly paved commercial

frontages. If the distance from the most remote point of the drainage area to the first

inlet exceeds 150 feet (45 meters), use the actual time of concentration assuming it is

more than the 15 minute/10 minute durations prescribed above.

1104.5 Hydraulic Design Procedure

As stated except that approved computer software may be used provided that all hydraulic

calculation data ordinarily furnished on the "Cuyahoga County Storm Sewer Computation

Form" is clearly presented for review by Cuyahoga County Highway Design Office

personnel. If all hydraulic calculation data noted above is not satisfactorily presented with the

computer software data, it will be necessary to additionally complete the ―Cuyahoga County

Storm Sewer Computation Form‖.

(1105) ROADWAY CULVERTS

1105.4 Design Procedure

1105.4.1 General

S.C.S. Method (TR-20) may be used within limitations, if approved by the County Chief

Highway/Bridge Design Engineer.

1105.4.2 Hydraulic Analysis

As stated except that all required hydraulic analysis/calculation data shall be additionally

provided on the "Cuyahoga County Culvert Calculation Form" for review by Cuyahoga

County Bridge/Highway Design Office personnel.

(1109) LONGITUDINAL SEWER LOCATION

1109.1 Under County Road Pavement

The designer shall make every reasonable attempt to locate longitudinal sewers so that they

are not under the pavement. Preferably, the storm sewer will be on the opposite side of the

roadway from the sanitary sewer. A minimum of six (6) feet (1.8 meters) clear distance

between storm and sanitary sewers should be maintained. Where this clearance cannot be

obtained, all portions of both the longitudinal storm and sanitary sewers, excluding minor

crossings; shall be constructed using premium jointed conduit for their full (manhole to

manhole) runs.


Manholes should not be located in the pavement or sidewalk unless no practical alternative

exists.

(1111) SANITARY SEWERS

1111.1 General

Sanitary sewers which are under the jurisdiction of the Cuyahoga County Sanitary Engineer

shall be designed in accordance with policies and criteria of the Cuyahoga County Sanitary

Engineer.

Sanitary sewers which are under the jurisdiction of the local municipality shall be designed in

accordance with the policies and criteria of the local municipality.


SUPPLEMENTS TO APPENDIX A

AND

THE DRAINAGE DESIGN AIDS

SUBJECT PAGE

No. 3C Catch Basin Bypass Charts 16-23








Cross Slope = 1" per foot 23

No. 3C Catch Basin Spacing Form Instructions 24

No. 3C Catch Basin Spacing Form (English Units) 25

No. 3C Catch Basin Spacing Form (Metric Units) 26

Cuyahoga County Storm Sewer Computation Form Instructions 27-28

Cuyahoga County Storm Sewer Computation Form (English Units) 29

Cuyahoga County Storm Sewer Computation Form (Metric Units) 30

Cuyahoga County Culvert Calculation Form (English Units) 31

Cuyahoga County Culvert Calculation Form (Metric Units) 32


CUYAHOGA COUNTY NO. 3C CATCH BASIN SPACING FORM INSTRUCTIONS

Column 1 Reference Number

Column 2 Station of inlet structure.

Column 3 Directional location of inlet structure.

Column 4 Runoff coefficient (See Section 1101.2.3 of the

O.D.O.T. Location and Design Manual).

Column 5 Average Rainfall Intensity in inches per hour

(millimeters per hour).

Column 6 Contributory drainage area in acres (hectares).

Column 7 Calculated inflow in cubic feet per second

(cubic meters per second).

Column 8 Bypassed flow from adjacent upstream inlet.

Column 9 Total flow into inlet in cubic feet per second

(cubic meters per second).

Column 10 Longitudinal slope, assumed parallel to

centerline profile.

Column 11 Cross slope of pavement (from typical section).

Column 12 From Pavement Flow Charts (O.D.O.T.

Location and Design Manual or Manning's

Equation).

Column 13 Gutter flow depth equals Column 11 x

Column 12.

Column 14 From attached bypass charts for Cuyahoga

County No. 3C Catch Basins. If O.D.O.T.

structure is otherwise used, from O.D.O.T.

Location and Design Manual, Figures 1100-20

thru 1100-110A.

Calculated By: Date: Rainfall Duration = tc = 15 Min. (Typ.) Project:Checked By: Date: I = 2.95 Inches/Hour (Typ.) ofDesign Frequency: 2 Years Allowable Spread (Ft.)

Max. Allowable Depth (In.)1 2 15

REM

ARKS

14

BYPA

SS

BYPASSCHARTS

(cfs)(cfs)(cfs)(cfs)(ACRES) (FT.)(FT.)(FT./FT.)(FT./FT.)

SECTIONA-A

SECTIONA-A

COLUMNS11 x 12"C" "I"

(IN./HR.)

"A" COLUMNS4 x 5 x 6

BYPASSCHARTS

COLUMNS7 + 8

CR

OSS

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FT.

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DATE: 06-01-2000

REF

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No.

STAT

ION

CUYAHOGA COUNTY ENGINEER No. 3C CATCH BASIN SPACING FORM (ENGLISH)

Sheet

INLE

TLO

CAT

ION

3 4 5

Calculated By: Date: Rainfall Duration = tc = 15 Min. (Typ.) Project:Checked By: Date: I = 75 mm/Hour (Typ.) ofDesign Frequency: 2 Years Allowable Spread (m)

Max. Allowable Depth (mm)1 2 15

DATE: 06-01-2000

REF

EREN

CE

No.

STAT

ION

CUYAHOGA COUNTY ENGINEER No. 3C CATCH BASIN SPACING FORM (METRIC)

(m/m) (m) (m3/s)

Sheet

INLE

TLO

CAT

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3 4 5 6 7

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"A" COLUMNS4 x 5 x 6

BYPASSCHARTS

COLUMNS7 + 8"C" "I" SECTION

A-ASECTION

A-ACOLUMNS

11 x 12

(m)(m/m)(m3/s)(m3/s)(m3/s)(HECTARES)(mm/HR.)

14

BYPA

SS

BYPASSCHARTS

REM

ARKS


CUYAHOGA COUNTY ENGINEER'S STORM SEWER COMPUTATION FORM

INSTRUCTIONS

Column 1 Structure type symbol.

Column 2 Station of pipe junctures.

Column 3 Directional location of structure.

Column 4 Incremental drainage areas in acres (hectares).

Column 5 Summation of drainage areas in acres (hectares).

Column 6 t = Time of flow in upstream pipe (minutes)

Column 7 t = Total time to this point (minutes).

Column 8 Rainfall intensity from rainfall intensity-

frequency duration curves, area "A" (10-year

storm).

Column 9 Rainfall intensity from rainfall intensity-

frequency duration curves, area "A" (25-year

storm).

Column 10 Runoff coefficient (See Section 1101.2.3 of the

O.D.O.T. Location and Design Manual).

Column 11 Incremental CA (Column 4 x Column 10).

Column 12 Total CA (Column 11 + Column 12 from

previous run within the same system).

Column 13 Discharge (Q10 = i10 x CA)(cfs) or (m3/s)

Column 14 Discharge (Q25 = i25 x CA)(cfs) or (m3/s)

Column 15 Size of pipe (Diameter in inches or millimeters

based on Manning's equation and 10-year

storm).

Column 16 Length of pipe section in feet (meters).


CUYAHOGA COUNTY ENGINEER'S STORM SEWER COMPUTATION

FORM INSTRUCTIONS (CONT.)

Column 17 Slope of pipe (Ft./Ft.)or (m/m).

Column 18 F/L elevation of inlet into structure.

Column 19 F/L elevation of outlet leaving structure.

Column 20 Actual depth of flow in feet (meters).

Column 21 Velocity using Manning's equation (Ft./Sec.) or

(m/s).

Column 22 Capacity using Manning's and continuity

equations (cfs) or (m3/s).

Column 23 Friction slope for Q25 using Manning's (Ft./Ft.)

or (m/m).

Column 24 Head loss in pipe section (Column 23 x

Column 16).

Column 25 Hydraulic grade line (25-year elevation).

Column 26 Inlet grate or manhole cover elevation.

Column 27 Reference remark(s) provided on back of

form(s) or on separate sheet(s)

Calculated By: Date: Manning's No. "n" : Project:

Checked By: Date: Manning's No. "n" : of1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

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SIZE

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LEN

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FRIC

TIO

NSL

OPE

(FT.

/FT.

)

HEA

DLO

SS (F

T.)

HYD

RAU

LIC

GR

ADE

LIN

E25

YR

. ELE

V.

GR

ATE

OR

M.H

.C

VER

ELE

V.

∆A �A ∆t �t i10 i25 C CA CA Q10 Q25 D L S0 EL EL d Vm (cfs) sf H EL EL

DATE: 06-01-2000ST

RU

CTU

RE

STAT

ION

SID

E

CUYAHOGA COUNTY ENGINEER STORM SEWER COMPUTATION FORM (ENGLISH)Just Full Capacity: 10 Yr. Frequency

Hydraulic Gradient: 25 Yr. Frequency (Typ.)

DR

AIN

AGE

AREA

(AC

RES

)

Sheet

TIM

E O

FC

ON

CEN

TRAT

ION

(MIN

UTE

S)

RAI

NFA

LLIN

TEN

SITY

(IN./H

R.)

DIS

CH

ARG

E(c

fs)

1 x �

CA

REM

ARKS

Calculated By: Date: Manning's No. "n" : Project:

Checked By: Date: Manning's No. "n" : of1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

RU

NO

FFC

OEE

FIC

IEN

T

CO

LUM

NS

4 x

10

CO

LUM

NS

11+1

2 Pr

evio

us

SIZE

OF

PIPE

(mm

.)

LEN

GTH

OF

PIPE

(m.)

SLO

PE O

FPI

PE (m

/m)

INLE

T PI

PE F

/L

OU

TLET

PIP

E F/

L

ACTU

AL D

EPTH

OF

FLO

W (m

)

MEA

N V

ELO

CIT

Y(m

/s)

JUST

FU

LLC

APAC

ITY

FRIC

TIO

NSL

OPE

(m/m

)

HEA

DLO

SS (m

)

HYD

RAU

LIC

GR

ADE

LIN

E25

YR

. ELE

V.

GR

ATE

OR

M.H

.C

VER

ELE

V.

∆A �A ∆t �t i10 i25 C CA CA Q10 Q25 D L S0 EL EL d Vm (cfs) sf H EL EL

RAI

NFA

LLIN

TEN

SITY

(mm

/HR

.)

DIS

CH

ARG

E(m

3 /s)

1 x �

CA

REM

ARKS

DATE: 06-01-2000ST

RU

CTU

RE

STAT

ION

SID

E

CUYAHOGA COUNTY ENGINEER STORM SEWER COMPUTATION FORM (METRIC)Just Full Capacity: 10 Yr. Frequency

Hydraulic Gradient: 25 Yr. Frequency (Typ.)

DR

AIN

AGE

AREA

(HEC

TAR

ES)

Sheet

TIM

E O

FC

ON

CEN

TRAT

ION

(MIN

UTE

S)

Calculated By: Date: STA. SkewCalculated By: Date: Project:Approved By: Date: Name of Creek: of

Storm Runoff Computed By:RATIONAL METHODU.S.G.S. REPORTSOTHER

MIN. = QD = TWD =QC = TWC =

MAX. =

DRAINAGE AREA:

HW

ID

HW

I (FT

.)

HW

ID

HW

I (FT

.)

H DC

TW

DC +

D2 H

0

LS0

HW

O (F

T.)

H DC

TW

DC +

D2 H

0

LS0

HW

O (F

T.)

CALCULATIONS:

BERM ELEV. - = AHW Ke =

CRITICAL PROPERTY - = AHW N =

Le =

CU

LVER

T D

ESC

RIP

TIO

NSI

ZE /

TYPE

/ M

ATE

RIA

L

ENTR

AN

CE

TYPE CHECK

STORM DESIGN STORM = YR.

DATE: 06-01-2000

CUYAHOGA COUNTY ENGINEER CULVERT CALCULATION FORM (ENGLISH)

SheetFINAL DESIGN SELECTION:

COVER ON FINAL SELECTION

QC = CHECK DISCHARGE (cfs)QD = DESIGN DISCHARGE (cfs)

(QD) O

UTL

ET V

ELO

CIT

Y (F

T./S

EC.)

REMARKS

CHECK STORM = YR.

OUTLET CONTROL HWO = H + h0 - LS0

HEADWATER COMPUTATIONINLET CONTROL

DESIGNSTORM

CO

NTR

OLL

ING

HW

CO

NTR

OLL

ING

HW

ELE

V.

BERM ELEVATION____________

INLET FLOW LINE ELEV. = _____ OUTLET FLOW LINE

ELEV. = ______

= ________ = ________

MAX COVER ELEVATION MIN COVER ELEVATION

S0 = _____LS0 = _____

_____ = AHW

TW = _____

Calculated By: Date: STA. SkewCalculated By: Date: Project:Approved By: Date: Name of Creek: of

Storm Runoff Computed By:RATIONAL METHODU.S.G.S. REPORTSOTHER

MIN. = QD = TWD =QC = TWC =

MAX. =

DRAINAGE AREA:

HW

ID

HW

I (m

)

HW

ID

HW

I (m

)

H DC

TW

DC +

D2 H

0

LS0

HW

O (m

)

H DC

TW

DC +

D2 H

0

LS0

HW

O (m

)

CALCULATIONS:

BERM ELEV. - = AHW Ke =

CRITICAL PROPERTY - = AHW N =

Le =

(QD) O

UTL

ET V

ELO

CIT

Y (m

//SEC

.)

REMARKS

CHECK STORM = YR.

OUTLET CONTROL HWO = H + h0 - LS0

HEADWATER COMPUTATIONINLET CONTROL

DESIGNSTORM

CO

NTR

OLL

ING

HW

CO

NTR

OLL

ING

HW

ELE

V.

DATE: 06-01-2000

CUYAHOGA COUNTY ENGINEER CULVERT CALCULATION FORM (METRIC)

SheetFINAL DESIGN SELECTION:

COVER ON FINAL SELECTION

QC = CHECK DISCHARGE (m3/s)QD = DESIGN DISCHARGE (m3/s)

CU

LVER

T D

ESC

RIP

TIO

NSI

ZE /

TYPE

/ M

ATE

RIA

L

ENTR

AN

CE

TYPE CHECK

STORM DESIGN STORM = YR.

BERM ELEVATION____________

INLET FLOW LINE ELEV. = _____ OUTLET FLOW LINE

ELEV. = ______

= ________ = ________

MAX COVER ELEVATION MIN COVER ELEVATION

S0 = _____LS0 = _____

_____ = AHW

TW = _____

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